Don't let his comment throw you off. "nearly 50% of voters", ie, the people that bothered to go out to vote. In reality, only 26% of eligible voters actually voted for Trump. This is why the complaints about voter suppression and gerrymandering are out there, because a small percentage is deciding the fate of the entire country. Heck, they didn't even get the most votes in this election, they just got saved by the electoral college system which is seriously rigged through gerrymandering currently.
I highly suggest you look up the definition of the term "gerrymandering". It has virtually no effect on a Presidential election. Here's a hint, state borders do not change every 10 years with the census...
And the only reason I said "virtually" is that 2 states (Maine and Nebraska) have the ability to split electoral votes giving the potential to gerrymander a grand total of 3 EC votes in the worst case scenario. Given that Trump did win a vote in Maine while losing the state (he won Nebraska and all districts - so no issue there), it's possible one EC vote was gerrymandered but you'd have to look at which party was in power in the state the last time the states districts were drawn.
As to popular vote, it has always been meaningless and reflects little. In the very "one-sided" states, voting is likely suppressed. I wouldn't be surprised, for example, if a large number of Republicans don't vote in California because their is no chance to win. Same for Texas and other ideologically lopsided states. And this works both ways.
That and the fact that voting rules are different for every state...some states have the polls open for a week, no excuse absentee balloting, longer hours, etc. To get a fair measure of a "true" popular vote is difficult at best. Without a lengthy analysis of each state and the effect of how the voting rules affects turnout in each state, and I have no idea how one measures the effect of demoralization in solid red and blue states, its essentially meaningless.
The worst thing about changing this to a popular vote...
Could you imagine a close race and a recount of each and every district in the entire country in order to determine a winner? You think it was bad this time with a recount of just a few states...
Since nothing is perfect, you'd have this political bickering and arguing over every changed vote in each and every state. That would be a nightmare.
Let's face it...the people arguing for a change to popular vote haven't really put a lot of thought into the issue. Seems to me they just want to find a way to change the results in favor of their candidate no matter the means.
Not to mention how every politician will only care about the biggest states. How would you like Federal tax cuts for just Texas New York and California? Nebraska needs a new bridge as it gets too old? Nah, not enough voters to be worth it... If you want to know why there is an Electoral College, it's precisely for this reason.